Control mechanism for mixing-machines



J. F. ROBB.

CONTROL MECHANISM FOR MIXING MACHINES.

/ APPLICATION FILED MAY 1. 1916.

Patented J an. 20, 1920.

3 SHEETS-SHEET l.

J. F. ROBB.

CONTROL MECHANISM FOR MIXING MACHINES.

APPLICATION FILED MAY 1. 1916.

1,328,765. Patented Jan.20,1920.

3 SHEETS-SHEET 2- iii @mmmmm I 1% h-woo I. a2, WMW

CONTROL MECHANISM FOR MlXlNG MACHINES.

Patented Jan. 20, 1920 3 SHEETS-SHEET 3.

APPLICATION FILED- MAY l, 1916- 1,328,765.

UNITED STATES PATENT OFFICE.

JOHN F. ROBB, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO KOEHRING MACHINE COMPANY, OF MILWAUKEE, WISCONSIN.

CONTROL MECHANISM FOR MIXING-MACHINES.

Specification of Letters Patent.

Patented Jan. 20, 1920.

Application filed May 1, 1916. Serial No. 94,754.

To all whom it maytconcem:

Be it known that I, J 01m F. Bonn, a citizen of the United States, residing at VVashington, in theDistrict of Columbia, have in- 'vented I certain new and useful Im rovements in Control'.Mechanism for} ixing-' Machines, of which the, following is a specification. I

It is well-known today that the recommendations and regulations governing the admixture of theaggregates for the construction of concrete work are becoming more and more rigid and exacting. The reason for this is the determination by engineers that the mixing of the loose materials including customarily cement, sand, gravel and water, must needs be. performed with great care in regard to all phases of the mixing operation; otherwise defective construction is the result. f

The improvements of the present invention appertain' primarily to mixing machines of the well known types used for mixing loose materials employed in cement or concrete construction, the object being to devise safeguarding control means for the various parts of the mixing machine whereby to insure that the materials operated 'on are mixed 3, sufiicient time to insure proper results.

It is prerequisite to the proper admixture of the loose materials used for cement work that once the mixing drum is charged with materials for a mixing operation, additional materials shall not be added to the batch in the drum until the time for the admixture of said particular batch has expired, and one of the important features of the present improvements has been to devise instrumentalities for this particular purpose. Thep'reventing instrumentalities just referred to involve the provision of positive means whereby to prevent operation of the drum charging device,- usually a loading skip, whereby to freshly charge the drum, until after the mixing operation upon the batch previously introduced into the drum has been completed.

Since the proper mixing of the loose materials for the purposes previously referred to is dependent to a large extent upon the number of movements or revolutions of the agitating means, usually a mixing drum, said number of revolutions bearing a predetermined and necessary relation to the time which the agitating device is required to operate for completing the mixing of a batch, another essential feature of the invention resides. in making provision necessitating that the agitating means shall be moving at a predetermined correct speed before it is possible to introduce the loose materials into the agitating device for ad mixture thereby.

The practical advantages of the improvements of this invention will be apparent on reference to the detail description supplied hereinafter, and it is to be understood that I do not wish to be limited to the special instrumentalities employed for controlling the operation of the charging and other main parts of the mixing machine because it will be evident that various other means may be employed whereby to establish the necessary interdependence of action of said parts through the provision of control means bearing greater or less similarity to that now to be set forth. In connection with the following description reference is also made to the accompanying drawings, in which- Figure l is a partial side elevation of a mixing machine of the general type to'which the present invention is preferably applied;

Fig. 2 is a fragmentary view showing more particularly the control devices in the closed casing provided for the same, the casing, however. being shown with the cover omitted to illustrate more fully the said devices;

Fig. 3 is a view partly in elevation and partly in section, showing more particularly the clutch mechanism by which the winding drum for elevating the loading ship is adapted to be rendered operative and inoperative as required;

Fig. 4 is a fragmentary view in side elevation bringing out more clearly the driving connection intermediate the mixing drum and the governor shaft;

Fig. 5 is a similar view showing the connections leading to the loading slides by which the movability of the clutch lever is controlled Fig. 6 is a sectional view through the casing containing the said locking slides and whereby the same are made inaccessible excepting to those authorized; and

Fig. '7 is a fragmentary and diagrammatic view of a modification involving lockclining downwardly into the drum B, to an I oppositely inclined position, acting as a mixing device in the first mentioned posi-' tion, and as a discharging device when in the last mentioned position.

The means for raising the loading bucket or skip C and controlling its descent includes suitable cables 1 connected with the bucket C and passing over suitable sheaves 2 on the framework of the machine to a point of connection with the small drums 3 on a shaft 4 mounted in the framework, said shaft 4 carrying a large drum 5 connected by a cable 6 with the winding drum 7, seen best in Figs. 1 and 3. The winding drum 7 is adapted to be operatively connected with the drive shaft 8, see Fig. 3, through the provision of suitable clutch mechanism of substantially usual construction. Said clutch mechanism, however, does include a clutch control lever 9 which is movable to the right 'as' seen in Figs. 1, 2 and 5, in order to cause winding of the cable 6 about the drum 7 in order to raise the skip C and thereby charge thedrum B with a batch of loose materials to be mixed.

The mechanism shown in Figs. 1 and 2 will now be briefly described to present the general control means whereby the proper admixture-of materials in the drum B is insured. This means includes a'drive shaft 10 5' see Fig. 4, geared to thedrum B, which shaft extends into the casing '11 mounted onltheframework of the machine and is supplied with a bevel gear 12 within the casing and arranged in mesh with a similar gear 13 on a governor shaftl l. The shaft 14: is thus driven at a'predetermined speed dependent upon the speed of the drum B wh'ich'is in turn driven by the motor D in the usual well known manner.

Centrifugally acting governor. balls 15 are connected with the shaft 14 and witha' collar '16 slidable onsaid shaft, said collar being; in turn connectedwith an indicator or controlling device'17 the han'd'of which is adapted to traverse anindicating plate 18 having, thereon the indications F for fast and S for slow, and Or for correct, referring to the speed of the drum and indicative of whether said speed is excessive, too much'reduced, or proper, whereby to obtain the correct admixture of the loose materials in the drum B within a time predetermined by the action of the control mechanism, as will now be set forth. The

shaft 14: carries a screw 19 turning therewith andwith which an interrupted thread or toothed portion of a knock-out member 20 is adapted to engage. The knock-out member 20 is slidable along a control lever 21 pivoted in the casing 11 at 22, said lever g in turn connected by a bell crank 23 with a rod24c.

The rod 2 1 is attached to a cam lever 25, a spring 26 encircling the lower end of said lever and being interposed between'thejparts 21 and 24. Another spring 27 has a bearing against the inner side'of the lever 25 and said lever has the cam arm'28 cooperative with atrip member 29 on the trip rod 30 The trip rod 30pa'ss'es vertically through the casing 11 and a spring 31 encircling said rod normally tends to force the same downward. At its upper endfthe rod is connected with a lever 32 exterior to the casing 11 and in turn connected with a rod 33, see Fig. 1, which leads to and is connected with an actuating lever 34 in the path of movement of the loading skip C. At its lower end the trip rod 30 is connected to a pivoted locking member 35. The locking member 35 is'adapted to engage a lug or other protuberance on the shaft 36 of the discharge chute E, whereby when the locking member is down the chute is locked against being moved for discharge purposes. A bell 37 in the casing 11 is i'n'a suitable electric circuit including batteries 38 and a circuit wire 39 leading to a contact 450, the latter disposed in the path of movement of an adjustable "screw member 41 carried by the knock-out member '26.

The action of'the-parts as thus far set forth is as follows: By operation of the clutch member 9 the clutch is adapted to be thrown in for driving the drum '7, and in'this manner the loading skip C is raised by the cables 1 to the inclined position shown in Fig. 1 wherein its contents are discharged into the drum B. In this action the'skip C strikes the lever 34 and through the connections described raises the trip rod 30 until the trip member 29the'reon cams against the arm 28 of the lever 25, tilting said lever. As the trip member 29 was lifted the spring 26 raised the outer end of the lever '21 partially engaging the knock-out member20 with the -screw 9, and the tilting of the lever 25"by the member 29 exerted'a pull on the rod 245shiftingthe bell crank 23 and completely engaging the members 19 and 20. Thereup'on the knock-out member 20 is caused to travel longitudinally of the lever 21 by the turning of the screw 19. It is contemplated that the adjustment of the knock-out member 20 in relation to the screw'19 be such that the time required for complete movement of the member 20 will be equivalent to the time required for a complete mixing operation of the loose materials of a batch introduced into the drum B.

When the trip member 29 is raised by the rod 30 it is maintained upraised by interlocking of the outer end of the cam arm 28 in a recess in one extremity of the trip 29. Thus it is that when the movement of the knock-out member 20 is completed the part 41 coacts with the lower end of the lever as well as with the contact 40 and simultaneously operates the signal bell 37 indicating completion of the time of mixing as required, and the movement of the lever 25 as just mentioned releases the trip member 29 and its rod 30 so that the latter are restored to the full line positions shown in,

Fig. 2. The release of the rod 30 raises the lock member previously lowered to lock the discharge chute against discharging, and the time of complete mixing of the materials in the mixer having been concluded, the operator may actuate the chute E and discharge the contents of the drum B.

The restoration of the member 29 and movement of the lever 25 as lastmentioned,

causes operation of the lever 20 to disconnect the knock-out member 20 from the screw, at the end of the traverse of said member 20, and a spring 20 connected with the member 20 pulls the knock-out member back to its initial position wherein the operation as set forth is susceptible of being repeated.

In actual practice, and speaking in relation to the size of a certain mixing drum as a certain instance, and having in mind, furthermore, the power operating means for said drum, we will say that the number of revolutions of the drum required for proper admixing will be within a minimum of 12 R. P. M. and maximum of 16 R. P. M. There are various conditions in relation to size and speed of the drum, and other conditions, which predetermine the time of admixture as of course incident to the number of revolutions of the agitating device.

Since it is essential, therefore, that the drum B shall be moving at the determined speed when the charge is introduced there into by means of the skip C, and having in mind that the actuation of the latter is controlled by the clutch lever 9, it is proposed by the present invention to establish interdependence of action between said clutch lever 9 and the indicator 17. This is done by providing an arm 17 on the indicator equipped with a roller adapted to engage a cam 42 so that the movement of the indicator may be imparted to the cam. The cam 42 is connected by a wire connection 43 with a locking member 44 movable in a lock casing 45 through which the clutch lever 9 passes intermediate its ends. The locking member 44 has a notch 44, see Fig. 5, into which the lever 9 is movable. When the drum D is turning more slowly than the required speed for proper mixing, or faster than such speed, the uninterrupted portion of the locking member 44 is held opposite the lever 9 owing to the pull exerted on the wire connection 43 through the action of the parts 17 and 42. Thus it is that until the determined mixing speed of the drum B is produced by the operator of the machine it is impracticable to throw the clutch lever 9 over to cause raising of the skip C. When, however, the correct speed of the drum B is reached, as indicated by the pointer of the indicator 17, said speed being anywhere between 12 and 16 R. P. M. in the instance at present described, the notch 44 of the member 44 will be opposite the lever 9, permitting the necessary clutch engaging movenlientcpf the lever for the raising of the s 1p Still another and important coaction between the lever 9 and the parts of the control mechanism is provided for by the use of instrumentalities" for preventing the clutch engaging movement of the lever 9, to raise the skip C for the purpose of adding materials to those in the mixer, before the time of completion of the mixing operation for the particular batch previously introduced. The last mentioned means involves the provision as seen best in Figs. 2 and 5, of a second locking member 46 preferably disposed, though not necessarily so, in the casing 45 adjacent to the locking member 44. The member 46 is connected by a wire connection 47 with the lower end of the trip rod 80, see Fig. 2. Thus it is that in the practical operation of the machine, if a batch of materials has been introduced into the mixing drum B the skip C will have raised the rod-30 andpulled u ward on the connection 47 to shift the loc 'ing member 46 into a position wherein its notch 46 is not opposite the lever 9. All during the time the rod 30 remains uplifted, which is the time required for the proper mixing of the materials now introduced into the drum B, the locking member 46 is held in the position stated and prevents a second operation of the clutch lever 9 which would be necessary if the operator wished to attempt to add additional materials to those in the drum. Such an attempt would therefore be prevented by the action of the part 46.

As seen in Fig. 5, the lever 9 is in its clutch engaging position, the parts being arranged in the positions maintained thereby when the drum B is rotating at the proper speed, and the clutch is in, or positioned properly for the raising of the skip C. Under these conditions a spring 46" intermediate the wire connection 47 and the locking member 46 is distended when the skip C strikes the lever 34 and raises the trip rod 30. In this manner power is stored up in the spring 46 which immediately takes effect, when the lever 9 is released at the end of the raising movement of the skip C, whereby to shift the locking member 46 to a locking position preventing a second raising movement of the skip. The elastic connection 46 is necessary for the reason that asth'e skip'C reaches its limit of up raising movement the parts 34 and 30 are actuated't'o exert a pull on the member 40 through the connection 47, which pull can not shift 'the'loeking member 46 until pressure on the lever 9 is released just as the skip reaches the limit of it's upward movement. The skip'C is lowered under control of a brake not shown.

As a substitute for the means previously set forth, the instrumen'talities illustrated in Fig. 7 may be used. In this case the means employed is electrical to some extent, involving the provision on the lower end of the rod 30 of a contact 48 adapted to close an electric circuit which includes the circuit wires 49 and 50 and a suitable source of electric current 51. Said electric circuit also includes the indicator 17 in such a manner that the latter constitutes a circuit closing and opening device. The wire 49 leads to a point of permanent connection with the indicator 1'? and the wire 50 to a contact member 52 with which coeperates a contact 53 movable with the indicator 17 on an arm extending from the latter. A solenoid 54 has its windingconnected in the electric circuit just described and the core member of said solenoid is constituted by an end portion of a locking member 55 cooperating with the lever 9 in somewhat-the same manner as described in relation to the locking members 44 and 46.

It will be evident that on y when the drum B is turning at the proper speed, at which time the indicator 1? maintains the contacts and'53 in cotiperation, will the locking member 55 be operable by the current passing through the solenoid 54 and held in a position in which the notch 55 is opposite the lever 9. Furthermore, the operability of the lever 9 in the last described arrangement is governed likewise by the contact 48 adapted to close the terminals of the electric circuit in a manner readily apparent on reference to the drawings. Owing to the last mentioned circuit closing means it is obvious that so long as the mixing of a batch in the drum B is going on the rod 30 is elevated and thesolenoid 54 deenergized, wherefore the locking member 55 prevents the operation of the lever 9 owing to the fact that the notch 55 is not opposite the lever 9, for which reason the lever remains locked. As soon as the time for proper mixing expires rod 30 is released and drops causing contact 48 to close the circuit including the solenoid 54. Then the solenoid actuates the locking member 55 to pull the same to release the lever 9 which release occurs when the notch 55 is opposite said lever. By the electrical means employed a singlelocking member 55 may be used and controlled from both the indicator l7 and the trip rod 30 to function in substantially the same manner as the locking members 44 and 46.

Owing to the provision of the locking and general controlling instrumentalities of this invention it will be apparent that no liability of introduction of loose materials into the drum B when the drum is not operatingat the correct-speed for the predetermined mixing operation, is incurred. Likewise, it isimpossible to add-materials to those of a batch previously introduced, until the completion of a thorough and proper mixing of said materials in the drum B. For the above reasons, and assuming that the casing 45 is provided witha suitable lock, as well as the casing 11, it is apparent that the degree of inspection required'to insure proper use of the mixing machine equipped with this invention is reduced materially as compared with-machines not having the safeguarding mechanism described herein.

The connections 43 and 47 are each conventional connections of the type comprising a flexible wirerendeied rigid so as to move longitudinally and around curves owing to being inclosed in a tube or casing of metal or other substance. v

Having thus described the invention, what is claimed-as new is 1. In con'ibinati'on, a mixing machine comprising a movable mixer, chargin means for the mixer, means for indicating the speed of-the mixer, and means for causingoperation of the charging means governed by said speed indicating means.

In a machine, the combination of a movable mixer, a charging device for said mixer, a-con'trollin device for said charging means operated in accordance with the speed of the mixer, means for operating the charging device, and means intermediate said controlling-device and said charging device operating means whereby the movement of the latter is governed by'the former.

3. In combination, a mixing machine commeans intermediate said controlling .devicev and said charging mechanism for preventing and permitting movement of the latter.

4. In a mixing machine, the combination of a movable mixer, driving means therefor, a charging device for the mixer, a control device for said charging device operated in accordance with the speed of the mixer, a lever controlling the operation of said charging device, and locking means for said lever releasable by said control device.

5. In a mixing machine, the combination of a movable mixer, means for operating said mixer, a charging device for the mixer, clutch operating means governing the action of said charging device and including an operating lever, a control device for said charging device operated from the mixer in accordance with the speed of the latter, and locking means for said operating lever operatively connected with said control device and movable thereby to shift the locking means for releasing the lever when the mixer is moving at a predetermined speed and maintaining the lever locked when the mixer is moving at other than said predetermined speed. I

6. In a mixing machine, the combination of a movable mixer, means for driving said mixer, a charging device for the mixer, clutch operating means governing the action of said charging device and including an operating lever, a" control device for said charging device operated from the "mixer in accordance with the speed of the latter, locking means for said operating lever operatively connected with said control device and movable thereby to shift the locking means for releasing the lever when the mixer is moving at a predetermined speed and maintaining the lever locked when the mixer is moving at other than said predetermined speed, a discharging device for the mixer, time controlled means preventing operation of said discharging device under predetermined conditions, and means for controlling the action of said first mentioned locking means from said time controlled means.

7. In combination, a mixing machine comprising a movable mixer, a charging device for said mixer, operating means for said charging device, and means for preventing said charging device from being operated by said operating means to charge the mixer for a predetermined time after introduction of materials into the mixer by the charging device.

8. In combination, a mixing machine comprising a movable mixer, a charging device for said mixer, operating means for said charging device, means for preventing charging operation of the charging device by said operating means for a predetermined time after introduction of materials into the mixer by the charging device, and controlling means for the last named means including a member operable by the charging device.

9. In combination, a mixing machine comprising a movable mixer, a charging device for said mixer, operating means for said charging device, means for preventing charging action of the charging device by said operating means for a predetermined time after introduction of materials into the mixer by the charging device, controlling means for the last named means including a member operable by the charging device, a discharging member for the mixer, and means whereby the action of the latter is controlled by the member operable by the charging device.

10. In combination, a mixing machine comprising a movable mixer, a charging device therefor, operating means for said charging device, locking means for preventing charging action of the charging device by said operating means, and time controlling mechanism operable by the movement of the mixer and governing the action tr said locking means.

11. In conrbination, a mixing machine comprising a movable mixer, a charging device for said mixer, operating means for said charging device, and means for locking said charging device against operation for a predetermined time after introduction of materials into the mixer by the charging device, and then automatically releasing the charging device from the locking means.

12. In combination, a mixing machine comprising a movable mixer, a charging device therefor, means for operating said charging device, lock means for said operating means and means controlled by the movement of the mixer for releasing said lock means.

13. In combination, a mixing machine comprising a movable mixer, a charging device therefor, means for operating said charging device, lock means for said operating means and means operable by the charging device for governing the action of said lock means.

14. In combination, a mixing machine comprising a movable mixer, a charging device therefor, means for operating said charging device, lock means for said operating means, means operable by the discharging device for governing the action of said lock means, and means operable in accordance with the speed of movement of the mixer also governing the action of said lock means.

15. In combination, a mixing machine, a charging device therefor, operating means for said charging device, lock means coacting to prevent charging action of said charging device by actuation of the said operating means, mechanism controlled by movement of the charging device and coacting with said lock means for preventing operation of the eperatim means for a predetermined time after tiie operation of the ha ing de i i 16. combination, a mixing machine, a charging device theref0r, operating means for said charging device, lock means coacting with the said operating means, mechanism controlled by movement of the charging device coacting with said lccl means for preventing operation of the operating means for a predetermined time after the operation of the charging device, and means operated by the mixer in accordance with the speed thereof governing the action of said lock means for prex'entlng operation of the operating means when the inixer is moving at a predetermined speed or speeds.

17. In combination, mixing machine comprising a movable mixer, discharge mean t ere har means the miter; eene'e l g' e e p rated y movement of the mixer, and means cansing operation of said charging means govned by aid, W F Hi device 4 combination, a mixing machine c prisin mova le m er, 'di d er means. the efor, eharg eg m et-1 fer the m er, epera e mea s h for and ea ee rel e b i ar n m n to ri enfi a sewed h gin eee atiefi by s i Q tatin e 11 .25 re eeme e rsed 1 9 Ja a Previ u we 12; n nii a a mix ng m h m risingmo abl x r," d scharge means therefor, charging means for the m xer, creating m an re e an 100kng m ns eentr l d. by t ehe mg ean and by the 0 .e etio e th mixe to prevent a second 0 arglng operationthereof taaa zcs until a predetermined elapsed time after a previous operation.

20. In combination, a mixing machine comprising a movable mixer, discharge means therefor, separate charging means for the mixer, separate lock means for preventing operation of the charging'ineans and the discharging means, and a control mechanism common to said lock means.

21. In combination, a mixing machine comprising 'a movable mixer, discharge mea s therefor, separate charging means forthe mixer, separate lock means for preventing operation of the charging means and the discharging means, and a control mechanism common to said lock means and governed in its action by the charging means.

' 22. In combination, a mixing machine comprising a movable mixer, discharge means therefor, separate charging means mixer, separate lock means for preventing operation" of the charging means and the discharging means, and a control mechanism common'to said locl; means and operable by the mixer.

23. In combination, a mixing machine comprising a movable mixer, discharge means therefor, charging means for the mixer, epa ate l c mean i r' Preventin per ti c th har i m ans a d h dis h r n Means, d a ee rel mechanism c n t S lo k means and g fverned in its action by the charging' neans and operable from the mixer.

In testimony whereof I' afiix my signature. 

